/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/

var a,b,c
new Promise((resolve,reject) =>{
    setTimeout(() => {
      a = 'hello'
      resolve(a)
    }, 10);
}).then(res=>{
    a = res
})
new Promise((resolve,reject) =>{
    setTimeout(() => {
      b = 'lagou'
      resolve(b)
    }, 10);
}).then(res=>{
    b = res
})
new Promise((resolve,reject) =>{
    setTimeout(() => {
      c = 'I♥U'
      resolve(c)
    }, 10);
}).then(res=>{
    c = res
    console.log(a + ' ' + b + ' ' +c)
})
